springboot 多模块 -- 将 dao(mybatis) 拆分出去
前言:
以前我们在建项目的时候, 要么将所有的package建在一个项目里面, 在处理引用的时候, 真的很方便. 不用担心, 有些东西配置不到或者读取不到.
或者, 将package独立出去, 到一个项目中或者子项目中. 这时候, 项目中的引用处理, 还是有些麻烦的. 不过好处更多, 不再表述.
在 idea 里面, 推荐使用 多模块 建项目, 而不再是 eclipse 里面的那种方式. 那这里, 就试着将一个springboot 的项目拆分到子模块中去, 看看效果如何.
项目拆分:
1. 目录变化
2. 父项目
父pom.xml理论上来说, 应该是对子项目中的引用进行一个约束, 主要是版本约束.
所以父 pom.xm 中, 应该使用 dependencyManagement 来约束 子项目中 jar 包版本.
然后对于一些子项目都用得着的引用, 可以提到 父项目中去.
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>cn.elvinle</groupId> <artifactId>parent</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>pom</packaging> <name>parent</name> <description>Demo project for Spring Boot</description> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.5.9.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <modules> <module>pojo</module> <module>web</module> <module>dao</module> <module>service</module> <module>simpl</module> </modules> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> <druid.version>1.1.3</druid.version> <mybatis.boot.starter.version>1.3.1</mybatis.boot.starter.version> <mysql.connector.java.version>5.1.44</mysql.connector.java.version> </properties> <dependencyManagement> <dependencies> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid</artifactId> <version>${druid.version}</version> </dependency> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>${mybatis.boot.starter.version}</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>${mysql.connector.java.version}</version> </dependency> </dependencies> </dependencyManagement> <!--申明依赖关系--> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
3. 子项目 - pojo
3.1 pom.xml
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>cn.elvinle</groupId> <artifactId>parent</artifactId> <version>0.0.1-SNAPSHOT</version> </parent> <groupId>cn.elvinle</groupId> <artifactId>pojo</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>pojo</name> <description>Demo project for Spring Boot</description> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
3.2 db实体
package cn.elvinle.pojo; /** * @author: elvin */ public class User { private int id; private String name; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } }
对于pojo和dao中的内容, 可以使用mybatis逆向工程生成, 可以省去很多麻烦.
4. 子项目 - dao
4.1 pom.xml
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>cn.elvinle</groupId> <artifactId>parent</artifactId> <version>0.0.1-SNAPSHOT</version> </parent> <groupId>cn.elvinle</groupId> <artifactId>dao</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>dao</name> <description>Demo project for Spring Boot</description> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <dependencies> <!-- 内部引用 --> <dependency> <groupId>cn.elvinle</groupId> <artifactId>pojo</artifactId> <version>0.0.1-SNAPSHOT</version> </dependency> <!-- 外部引用 --> <!-- https://mvnrepository.com/artifact/com.alibaba/druid --> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid</artifactId> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
4.2 mapper
UserMapper.java:
public interface UserMapper { public List<User> getAll(); }
UserMapper.xml:
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" > <mapper namespace="cn.elvinle.dao.mapper.UserMapper" > <select id="getAll" resultType="cn.elvinle.pojo.User"> select * from user </select> </mapper>
5. 子项目 - service
5.1 pom.xml
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>cn.elvinle</groupId> <artifactId>parent</artifactId> <version>0.0.1-SNAPSHOT</version> </parent> <groupId>cn.elvinle</groupId> <artifactId>service</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>service</name> <description>Demo project for Spring Boot</description> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>cn.elvinle</groupId> <artifactId>pojo</artifactId> <version>0.0.1-SNAPSHOT</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
5.2 UserService.java
public interface UserService { public List<User> getAll(); }
6. 子项目 - simpl
6.1 pom.xml
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>cn.elvinle</groupId> <artifactId>parent</artifactId> <version>0.0.1-SNAPSHOT</version> </parent> <groupId>cn.elvinle</groupId> <artifactId>simpl</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>simpl</name> <description>Demo project for Spring Boot</description> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>cn.elvinle</groupId> <artifactId>pojo</artifactId> <version>0.0.1-SNAPSHOT</version> </dependency> <dependency> <groupId>cn.elvinle</groupId> <artifactId>service</artifactId> <version>0.0.1-SNAPSHOT</version> </dependency> <dependency> <groupId>cn.elvinle</groupId> <artifactId>dao</artifactId> <version>0.0.1-SNAPSHOT</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
6.2 UserSImpl
@Service public class UserSImpl implements UserService { @Autowired private UserMapper userMapper; @Override public List<User> getAll() { System.out.println("UserSImpl getAll"); return userMapper.getAll(); } }
7. 子项目 - web
关键的地方来了.
7.1 pom.xml
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>cn.elvinle</groupId> <artifactId>parent</artifactId> <version>0.0.1-SNAPSHOT</version> </parent> <groupId>cn.elvinle</groupId> <artifactId>web</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>web</name> <description>Demo project for Spring Boot</description> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>cn.elvinle</groupId> <artifactId>simpl</artifactId> <version>0.0.1-SNAPSHOT</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
7.2 application.yml
server: context-path: /parent port: 8080 mybatis: config-location: /mapper/*.xml spring: datasource: username: root password: root url: jdbc:mysql://localhost:3306/shop?useUnicode=true&characterEncoding=utf-8 driver-class-name: com.mysql.jdbc.Driver
7.3 控制器
@RestController @RequestMapping("api") public class ApiController { @Autowired private UserService userService; @RequestMapping("index") public List<User> index(){ List<User> all = userService.getAll(); return all; } }
到目前为止, 没什么特别的, 都是正常修改, 接下来, 会出现与不分模块不同的地方.
7.4 入口处修改
@ComponentScan({"cn.elvinle"}) @SpringBootApplication public class WebApplication { public static void main(String[] args) { SpringApplication.run(WebApplication.class, args); } }
这时候, 如果直接运行起程序, 是不会成功访问的. 原因在于, mybatis的自动化配置和自动化创建, 没有支持到多模块中.
这时候, 需要我们手动进行配置和创建.
7.5 Mybatis java 配置
<!-- mybatis 的工厂 --> <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"> <property name="dataSource" ref="dataSource" /> <property name="configLocation" value="classpath:mybatis/SqlMapConfig.xml"/> <!-- 自动扫描mapping.xml文件 --> <!--<property name="mapperLocations" value="classpath:mapper/*.xml" />--> </bean> <!-- DAO接口所在包名，Spring会自动查找其下的类 --> <bean id="mapperScannerConfigurer" class="org.mybatis.spring.mapper.MapperScannerConfigurer"> <property name="basePackage" value="cn.elvinle.bookshop.mapper" /> <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/> </bean>
可以对照着上面的配置文件, 进行java配置
MybatisConfig:
@Configuration public class MybatisConfig { @Value("${mybatis.config-location}") private String mapperLocationPattern; @Bean @ConfigurationProperties(prefix = "spring.datasource") public DataSource dataSource(){return new com.alibaba.druid.pool.DruidDataSource(); } @Bean(name="sqlSessionFactory") public SqlSessionFactory sqlSessionFactory() throws Exception{ SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean(); sqlSessionFactoryBean.setDataSource(dataSource()); PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver(); sqlSessionFactoryBean.setMapperLocations(resolver.getResources(mapperLocationPattern)); return sqlSessionFactoryBean.getObject(); } }
MybatisMapperScannerConfig:
@Configuration @AutoConfigureAfter(MybatisConfig.class) @MapperScan("cn.elvinle.dao.mapper") public class MybatisMapperScannerConfig { public MapperScannerConfigurer mapperScannerConfigurer(){ MapperScannerConfigurer mapperScannerConfigurer = new MapperScannerConfigurer(); mapperScannerConfigurer.setSqlSessionFactoryBeanName("sqlSessionFactory"); mapperScannerConfigurer.setBasePackage("cn.elvinle.dao.mapper"); return mapperScannerConfigurer; } }
OK, 到这里, 就可以把程序跑起来了, 看一下结果:
